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Патент USA US2120056

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June 7, 1938.
Original Filed July 31, 1933
jKA [7y 5 6/455
Patented June 7, 1938"
Ira E. McCabe, Chicago, Ill.
Original application July 31, 1933, Serial No.
683,037. Divided and this application Febru
ary 11, 1935, Serial No. 5,931
5 Claims.
(Cl. 201—48)
This invention. relates to improvements in
switching systems and more particularly to a
combined resistor and shunt switch for use in
such ‘a system. This application is a division of
5 this applicant’s prior copending application Serial
No. 683,037, ?led July 31, 1933.
It is an object of this invention to provide an
electric switch so constructed that when the circult is ?rst established therethrough to include
10 an electrical resistance in said circuit and upon
operation of the switch to shunt out the resistance and allow the full current to pass therethrough. It is a further object of this invention
_ to include a resistor in a mercury tube switch
15 which will‘be shunted out when the switch has
been tilted to cause the mercury to contact the
electrodes thereof.
Such combined resistor and shunt switches are
of advantage when delayed action is desired in
20 controlling the operation of an electric motor
and more particularly in connection with controlling reversing motors as disclosed in said
parent application.
between the opening of the running circuit and
the closing of the reversing circuit and vice versa. 5
The control of such‘ motors is usually accom
plished through remote control switches which
open and close the motor circuits and additional
mechanism is required to provide the delay neces
sary between the closing of the motor circuit and 10
the operation of the motor.
The additional mechanism is interposed be- _.
tween the source of the current and the motor
and caused to function upon the opening and
closing of the remote control switch to immedi- 15
ately open the circuit to the motor and there
after allow a period for slowing up or stopping
of the motor before closing the reversing circuit,
to provide always a positive delay in the break
ing of one motor circuit and making the reversing 20
circuit, following the operation of the remote con
trol switch, regardless of how rapidly the control
, '
It is preferable in the delay switch operating
mechanism to use the repulsion relay such as dis- 25
closed in this applicant’s co-pending application,
Serial No. 508,185, ?led January 12, 1931, now
Patent No. 1,973,925 of September 18, 1934, which
is adaptable for use with either alternating or
In the drawingFlgure 1 is a view partly in front elevation and
partly in diagram, illustrating an application of
this invention as‘disclosed in said parent appli35
To avoid damage, or unnecessary abuse to re
versing motors, or equipment operated thereby; it
is often necessary or desirable to provide a delay
switch is caused to operate.
With these and other objects in view, reference
25 is made to the’ accompanying sheet of drawings‘
which illustrates an embodiment of this invention with the understanding that detail changes
may be made without departing‘ from the scope
direct current or the relay disclosed in this ap- 30
plicant’s co-pending application, Serial No.
500,747, ?led December 8, 1930, which may be of
the transformer type permitting the use of low
voltage remote control ‘equipment, and in con
Figure 2 is a view in longitudinal vertical central section of this improved switch, shown in
nection with the relays to employ an electrical 35
resistor in the control circuit. The resistor con
the open position with parts shown in side elevation.
Figure 3 is a view similar to ‘Figure 2 showing
40 this improved switch in closed position.
Figure 4 is a top plan view of Figure 1.
templated may be any of the resistance elements,
which offers great resistance to the passage of
electric current therethrough when cold, but as
its temperature increases, due to the passage of 40
current therethrough its resistance decreases
For a better understanding of the advantages ‘ until a large amount of current is passable. Such
and peculiar construction of this improved com- elements are known in the art and one known
bined resistor and shunt switch, it is deemed ad-_ as Durhy, an electric vfurnace product having as
45 visab'le to ?rst brie?y describe a practicable com- its base silicon carbide with a very high dissocia- 46
mercial application of this novel switch before
defining its peculiar construction. With this object in view,‘ reference is made to Figure 1 of the
drawing which shows in diagram the application
tion temperature, is manufactured by the Globar
Corporation of Niagara Falls, New York.
The control for a. reversing motor shown in
Figure 1 includes an electric motor M and two re
50 of this switch in controlling the operation of a lays comprising a rectangular core C with a sta- 50
reversing motor, as more specifically disclosed in tionary primary coil P secured to the center of
this applicant's parent application, Serial No. the upper leg thereof with movable secondary
683,037. filed July 31, 1933, with the understand- coils S mounted upon the same leg on each side
ing that by so doing the use of this invention is’ ,of the stationary coil P. The switch‘ carrying
55 in no way limited to this single use.
arms I are pivotally mounted at I“ to the lower ’
leg of the core C and are each secured at their
upper ends to their respective secondary coils.
The arms I] are extended downward on opposite
sides of the lower leg to which they are pivoted
and the lower ends of each arm supports a motor
switch MS and a shunt switch SS, as shown, so
that the weight of said switches normally main
tain the coils S in contact with the coil P.
The binding post is connected to one side L
of the source of commercial current and also to
one winding of the primary coil
the other wire
of which is connected through the binding post
3 to the return line L’ commercial ‘current. The
binding post 2 is connected through the motor
switch operated by the left hand coil S to bind
ing post ii and thence through the motor to op
erate it in the forward direction to the binding
post 3. The binding post 22 is also connected
through the motor switch MS on the right hand
20 side to the binding post 5 and thence through
the motor to operate it in reverse direction to
binding post 3. in this form, one end of the
windings of each of the secondary coils S are
connected through their respective shunt
25 switches SS to binding post ii and from thence
to the remote control switch BC. The contact
‘I adapted to be engaged by the remote control
switch is connected to the other end of the wind
ing of the secondary coil upon the right of the
30 primary coil and the contact t adapted to be en
'gaged by the remote control switch is connected
to the other end of the secondary coil upon the
left of the primary coil.
In this form, the shunt switches SS are identi
35 cal and each one is a mercury tube switch espe
cially constructed to act as both a resistance ele
ment and as a shunt switch, as shown in Figures
switch and shunt switches are closed. The clos
ing action of the shunt switch causes the mer
cury 02 therein to contact the terminals '9 and i I
to establish the circuit through the resistor R
and as the switch is tilted the mercury itself not
only shunts out the resistor R but as it submerges
the resistor R also has a cooling effect and accel
erates the reduction in temperature‘ of the re
sistor so that upon rapid switching of the remote
control BC the delay, resulting from the heating 10
of the resistor, will not be shortened.
What I claim is:
i. A combined resistor and shunt switch in
cluding an envelope having terminals sealed in
the walls thereof, an electrical resistor having a 1
negative temperature coefficient interposed be
tween the terminals to be always connected in
circuit therewith, and a movable body of conduct
ing ?uid which, in one position of the switch,
moves away from the resistor and terminals to be 20
completely out of contact therewith, and, in an
other position of the switch moves to submerge
the resistor and shunt it.
2. The structure of claim 1 in which the ter
minals are engaged by the fluid before the re 25
sistor is submerged.
3. The structure of claim 1 wherein the ter
minals are simultaneously engaged and the cir
cuit closed by the conducting ?uid before the
fluid engages the resistor.
4. In a mercury tube switch, a sealed‘ glass en
velope containing a movable body of mercury,
electric terminals sealed in one end thereof one '
above the other, the upper terminal bent at an
angle within the envelope to end- in the same 35
plane and in line with the end of the lower ter
minal, said lower terminal offset within the en—
2, 3 and 4. As shown, the lower terminal 9 is
velope adjacent the wall thereof, and an electric
provided with an o?set I0 adapted to engage one
40 end of the resistor element R and the upper ter
-minal H is brought down to contact the other
end of the resistor R and hold the same ?rmly in
resistor having a negative temperature coefficient
interposed between said oifset terminal and end
of the upper terminal to be always in circuit
therewith, whereby when the mercury is con
tained in one end of the envelope, it is out of
contact with the said terminals and resistor and
upon ?owing into the other end, the mercury
shunts the resistor and reduces its temperature.
5. A combined resistor and shunt switch in
cluding a tiltable mercury tube switch containing
a body of mercury and two spaced apart ter
position between the two terminals at the bottom
of the mercury tube switch. The resistor is pro
45 vided with metal caps RR to which the ter
minals are welded. By this construction‘ when
the remote control switch opens the circuit
through a secondary coil, the weight of the
switches carried thereby returns it to contact
50 with the primary coil and opens both of said
switches, so that when the remote control switch
reestablishes the circuit through the secondary
coil, the current passes through the resistor in
the open shunt switch causing a delay in the
55 movement of the secondary coil until the re
sistor has increased su?iciently in temperature to
allow su?lcient current to pass therethrough to
repel said secondary coil, whereupon the motor
minals extending thereinto normally out of con- 1
tact with the mercury, in combination with an
electrical resistor having a negative temperature
coei?cient interposed between the terminals to be
always in circuit therewith and to be free of said
mercury upon tilting the switch in one direction ~
and be submerged and shunted by said mercury
upon tilting the switch in the other direction.
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